Diseases caused by trypanosomes and related organisms afflict millions of people in Africa, Asia, and other tropical and subtropical regions of the world infections are manifested in many tissues and organs and the symptoms are diverse, ranging from immunosuppression to blindness and often death. Treatment of these infections currently requires chemotherapy, is of only limited effectiveness, and is toxic for the patient. Trypanosomes, the parasites that cause these diseases, are single cell protozoans that diverged early from other protist species. As a result of their early evolutionary divergence, these organisms exhibit many unusual genetic and biochemical characteristics which may reveal possible points of inhibition to reduce pathogenesis of these organisms. This research will involve the genetic characterization and application of "ribozyme" technology to knock out specifically targeted Trypanosoma mRNAs.